Optimum health, functioning and nutritional status are key to the quality of life in the older American. More than 35 million Americans are over the age of 60, and the oldest old represent the fastest growing segment of the American population. Approximately 25% of those over 50 and more than 60% of those over 80 years have olfactory impairment (Murphy et al., 2002). Furthermore, olfactory function is significantly affected in Alzheimer's disease, a devastating disease that affects more than 5 million older Americans. Its personal and financial impact on the individual, the caregiver(s), the health care system and society are profound. Although the psychophysical and perceptual manifestations of age-related olfactory impairment are known, tie underlying neural causes are unclear. The present application will employ neuroelectric topographic mapping procedures to image the aging brain during odor information processing in order to test the overarching hypothesis that functional changes in central nervous system (CNS) activity, detectable in EEG/ERP activity, reflect chemosensory loss in aging. To accomplish this goal we have developed olfactory event-related potential (OERP) techniques that can be applied in multi-electrode arrays and the stimulation techniques necessary to present olfactory stimuli with precise timing. These paradigms probe odor memory processes particularly vulnerable to aging and dementia. These methods will provide substantial information about the magnitude and timing of normal age altered CNS activation patterns in comparison to those at risk for cognitive impairment from dementing illness. Neuroelectric measures that reflect olfactory CNS impairment may serve as a marker for dementia and, therefore, have considerable potential clinical significance. The results of this project will deepen our understanding of changes in olfactory processing in the aging brain in health and disease. Impairment of chemosensory and specifically olfactory function can negatively impact dietary selection, nutritional status, morbidity and mortality in older persons (Schiffman, 1997). A better understanding of chemosensory function may suggest avenues to optimize health and quality of life in older adults.